Paper bag backing?

[George Elkstalker]

What is the paper bag backing method?

[monterey]

George, I don't have a clue!  That said, I just got done putting a paper bag backing on a small oak kid bow.  I smeared elmers wood glue on it and laid the paper down.  Got feeling like experimenting so on one end I used dry paper and the other I wet the paper before putting it down.  It's still drying so I'll know more tomorrow and will give you an update.

There's probably some folks here who have much more experience at it.  I'm looking forward to seeing there comments too.

[Pat B]

Brown paper is strong by itself because of the fibers that make it up and when glue is added it becomes quite a bit stronger. It is a simple backing that will add some protection to a board bow. It won't add any performance. Back in the 40s, paper bow backings were common.

[razorback]

I have been using paper drywall tape. Easy to dispense and has a line that helps to maintain the center line. I think it should be as good as brown paper. i apply it dry, but will be interested to know if I should wet it first or size it.

[Pat B]

Dry wall paper tape is probably very similar to brown bag paper.

[monterey]

Well, here's how it came out:

 

The third from the left is the paper bag backing.  From the left is fiberglass mat (automotive body repair) glued with epoxy, 10 oz cotton duck glued down with wood glue, paper bag and wood glue and far right is thin rawhide glued uder pressure with gorilla glue.

The paper bag is by far the easiest to work with and the least expensive backing of the four.

These are all four 48" pyramid kid bows under construction.

I'll probably make more of these and at this time I'm leaning toward more paper bag backings

[Pat B]

Now you have a nice pallet for the new owner to put the design of his or her liking1

[monterey]

Yes, it will be interesting to see what they come up with.

[UnderControl16]

I've used Oak to make a self bow also and i haven't put a backing on it. Should i putting a backing on it/do i need a backing? What does a backing do anyway aside from give you something to put a design on? Sorry a bit of a noob when it comes to all this...

[razorback]

Different backings have different properties. For the most part they help protect the back of the bow from developing problems like splinters. Paper, silk, linen, rawhide and fiberglass drywall tape, provide this stabilizing platform. Some wooden backing and sinue can also be used to help the bows performance as well as providing protection. if you have a clean bow back without any grain runouts then you probably do not need to back your bow. Post some pic's and someone will be able to give you a better answer.

[Brently]

I have made a hickory bow with  paper bag backing.  I tried making it 5 layers thick.....mistake, the backing cracked, I thinned the paper down to @ 2 layers and no problem.  Just some advise so you won't make the same mistake s I did.

[Pat B]

Having too many layers of backings can be more detrimental to the bow(physically and performance wise) than no backing at all. In most cases a non-performance backing(paper, silk, linen, rawhide, etc) will not prevent bow breakage. It is not a miricle cure. It is insurance to HELP prevent breakage. If you use a crappy board or stave one of these backings will not make it a good board or stave.
   Understanding the physics of the stresses in a working bow will get you closer to success than adding a backing to prevent breakage. A backing is a last resort!
   Five layers of any backing will move the neutral plane into a material that can't necessarily take the stresses. A single backing will help to hold down splinters that may occur as the bow's back goes onto tension. Multi backings add physical weight that will reduce the recovery of your limbs plus the tension stresses will overpower the multi backing causing it to break and that break will usually travel down into the bow wood. You are actually setting yourself up for failure.

[LoneWolf]

A little off topic, but what do you glue the fiberglass drywall tape down with?  Have some of it left over and need to back a bias grain kids bow I am building.

[Pat B]

I've never used FG tape but TBIII glue would work fine.

[AKmud]

I've made 4 or 5 red oak board bows now and used the fiberglass drywall tape along with TBIII and it has worked pretty well.  The bows have all been under 40# though.  I've got one oak board bow that is 40# with no backing, but I have some finishing to do yet.

I recently made a set of hickory bows that I didn't back and they seem to be solid.  One is 45# and the other 50#.

I've been thinking of trying a veneer like cabinet makers use as backing.  The stuff comes in 4x8 sheets and exotics are easy to find.  

I just bought an ash board and a jatoba board to try some bows from.  They are both really hard so is there any reason to back them?  If so, what would be a good combination?

[Pat B]

Hardness doesn't necessarily matter. The grain configuration on the back does!
  Generally for the denser hardwoods, bamboo or hickory makes a good backing. For just protection, I'd go with rawhide, silk or linen.

[monterey]

AKmud,  I'm curious about the fiberglass drywall tape you use.  Looked at some in the hardware store yesterday and it had it's own adhesive backing.  Is that you use?  If so, how do you deal with the existing adhesive?